The Premier League champions face Chelsea in the Community Shield on Sunday before opening the defence of their title the following weekend against newly promoted Southampton.

However, the former the Inter Milan boss is wary of some of his stars lacking match fitness, with players such as David Silva and Mario Balotelli given time off following Euro 2012, and believes their recent pre-season games have been vital to their preparations.

"The games against Oldham and Limerick were very important, but I think we need another three or four weeks for these players to get back to full fitness," Mancini told the club's official website.

"We will all need to work very hard at Carrington. We will start to work together, the whole team together as we prepare for the season ahead.

"For us it was important that the players play in the European Championship, but they needed a month to recover because last season was very hard and this season will be very long."